1. Technical Field
This invention relates to aircraft fiber-optic control systems, and in particular to opto-electric/hydraulic servoactuation.
2. Background Art
Aircraft and aerospace vehicle flight operation depend on the correct operation of flight control surfaces. The flight control surfaces of present advanced vehicles are operated by Fly-By-Wire (FBW) hydraulic actuators, where digital/analog electronic controls provide the control signals for the electrohydraulic actuators.
The flight control actuators are usually located in aircraft where they are sensitive to generic failures from EMI, EMP, RFP and lightning threats due to type of vehicle-structural materials used or lack of protection incorporated. The FBW actuation technology is well developed, and has been successfully used in certain high performance aircraft for flight control actuation. Excellent performance, reliability and maintainability have been achieved, but the system has a weakness; that of, sensitivity to generic-environmental failures. This problem can be solved or minimized through protection, such as shielding with heavy weight penalties.
In contrast, the present invention offers another solution through the usage of fiber-optic technology, called Fly-By-Light (FBL) signaling. The FBL signal transmission is immune to these generic failures. This new emerging technology can provide the proper signal transmission for actuation, which can be comparable to FBW signaling with respect to performance, reliability and maintainability; in addition to insensitivity to generic failures.
In the patent literature, U.S. Pat. No. 4,443,853 to Maciolek et al. shows an electrically controlled mechanical actuator driven by optically generated electrical power through an optically controlled switch in an electrically isolated module. Maciolek et al. however, in contrast does not show the use of dual coil with diode control, nor optically controlled dual switches, nor a power supply circuit for the dual solar cells, nor the dual servoamplifiers, nor the RS dual optical links as exemplified by embodiments of the present invention.
Further exemplary of the prior art is U.S. Pat. No. 4,132,278 to Stevens which relates to a control system for aircraft including electrohydraulic valve means, however in contrast to the present invention does not use optical means for power transfer, but uses hydraulic power exclusively to produce electrical power.